What is a suntan?
What happens when a person gets a suntan? How long will it take to get suntan?
Why sunburns happen?
I’m going to explain these and other questions today!
Why our skin is getting darker during sunny days?
In my previous post about skin (What skin actually is?) I didn’t mention one important skin component -melanocytes. In those cells the pigment of the skin is produced. Melanocytes are located in the stratum basale in the epidermis. Many complicated, enzymatic reactions take place there and all of that is a process called melanogenesis. UV radiation activates this process. The end product of these enzymatic reactions is melanin, which is then stored in the melanosomes.
Melanosomes are intercellular vesicles and contain two types of melanin
pheomelanin - a red-yellow form
and
eumelanin - a brown-black form
Next, melanosomes are transported to the epidermis cells, where under influence of UV radiation among others, they crack and release melanin inside keratinocytes. That is the answer to your question on “Why every summer I’m getting that amazing suntan?”
Melanosomes of people with darker skin are bigger and more numerous. The transfer of the pigment to the keratinocytes takes place in more superficial layers than transfer of the pigment in pale-skinned people, because of that, colour becomes darker and longer-lasting.
For what purpose is melanin transported to keratinocytes?
It forms a defence system of your skin! Melanin protects your skin from UV light.
But is that protection system rapid enough?
Many times in our lifetime, we observed sunburn on top of our nose, shoulders and other places. Melanocytes have a slow response, because of that, the first days of sunbathing are crucial for our health and beauty. Next time think about it whilst laying on the beach. Even if dark-skinned people have greater protection, they still risk sun damage.
Ultraviolet radiation contained in sunlight is noxious for our skin! It is a reason of skin ageing, not to mention skin cancers…
- UVA penetrate to the dermis, but even to the hypodermis! It result in damage to collagen and elastic fibres, leading to a decrease in skin elasticity. This leads to wrinkles and skin sagginess. UVA can penetrate even through the glass, so ALWAYS remember about proper sun protection! SPFs and healthy suntan is a subject for a separate post and definitely you’ll find information here in one of the next postings. So remember to follow me and come back to the blog regularly. You don’t want to miss that 😊
- UVB reaches to the basal layer of the epidermis, causing sunburns and DNA mutations, leading to skin cancer. UVB do not penetrate glass, but can penetrate water. Therefore wet clothes DON’T PROTECT us from UVB radiation! Remember about it when you finish swimming! Your wet swimming costume doesn’t work as a UVB shield.
However reasonable UV exposure can be beneficial, but only in small amounts: It’s important for the synthesis of vitamin D3 and to help increase absorption of calcium.
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